The Flattened, Rotating Molecular Gas Core of Protostellar Jet HH 212

Wiseman, Jennifer; Wootten, Alwyn; Zinnecker, H.; McCaughrean, M. J.

doi:10.1086/319474

Cited by 56 publications

(91 citation statements)

References 22 publications

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“…These authors demonstrated the velocity signature to be consistent with a simple jet rotation model. The value is also in the same range as those measured in H 2 emission for HH 212 SK1 by Davis et al (2000), in which the authors point out that the expected jet rotation speed based on the disk rotation measurements of Wiseman et al (2001) is ∼2 km s −1 , thus demonstrating that our measurements are consistent with a jet rotation interpretation. It is also clear from the modeling of Correia et al (2009) that the toroidal velocity may be confused with other kinematic signatures, and so our calculations are broad indications.…”

Section: Discussionsupporting

confidence: 83%

“…This was interpreted as such given the agreement with the sense of a radial velocity gradient across the disk of the same system (Wiseman et al 2001). Codella et al (2007) report no sign of jet rotation in the SiO emission near NK1, whereas in the region SK2−SK4 (∼10−14 from source), they find a gradient in a direction contrary to that reported for SK1 by Davis et al (2000).…”

Section: Hh 212 Nk1 and Sk1mentioning

confidence: 53%

“…Codella et al (2007) report no sign of jet rotation in the SiO emission near NK1, whereas in the region SK2−SK4 (∼10−14 from source), they find a gradient in a direction contrary to that reported for SK1 by Davis et al (2000). It is therefore also contrary to that of the disk which has a 5 km s −1 difference between the blue-shifted ammonia gas in the north-east and the red-shifted Claussen et al 1998;(8) Wiseman et al 2001. gas in the south-west (Wiseman et al 2001). However, Lee et al (2008) recently conducted a higher resolution rotation study of the HH 212 flow and report matching gradients in the southern and northern lobes of the SiO jet in a sense that also matches that of the disk.…”

Section: Hh 212 Nk1 and Sk1mentioning

confidence: 99%

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Searching for jet rotation in Class 0/I sources observed with GEMINI/GNIRS

Coffey

Bacciotti

Chrysostomou

et al. 2010

A&A

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Context. In recent years, there has been a number of detections of gradients in the radial velocity profile across jets from young stars. The significance of these results is considerable. They may be interpreted as a signature of jet rotation about its symmetry axis, thereby representing the only existing observational indications supporting the theory that jets extract angular momentum from stardisk systems. However, the possibility that we are indeed observing jet rotation in pre-main sequence systems is undergoing active debate. Aims. To test the validity of a rotation argument, we must extend the survey to a larger sample, including younger sources. Methods. We present the latest results of a radial velocity analysis on jets from Class 0 and I sources, using high resolution data from the infrared spectrograph GNIRS on GEMINI South. We obtained infrared spectra of protostellar jets HH 34, HH 111-H, HH 212 NK1 and SK1. Results. The [Fe II] emission was unresolved in all cases and so Doppler shifts across the jet width could not be accessed. The H 2 emission was resolved in all cases except HH 34. Doppler profiles across the molecular emission were obtained, and gradients in radial velocity of typically 3 km s −1 identified. Conclusions. Agreement with previous studies implies they may be interpreted as jet rotation, leading to toroidal velocity and angular momentum flux estimates of 1.5 km s −1 and 1 × 10 −5 M yr −1 AU km s −1 respectively. However, caution is needed. For example, emission is asymmetric across the jets from HH 212 suggesting a more complex interpretation is warranted. Furthermore, observations for HH 212 and HH 111-H are conducted far from the source implying external influences are more likely to confuse the intrinsic flow kinematics. These observations demonstrate the difficulty of conducting this study from the ground, and highlight the necessity for high angular resolution via adaptive optics or space-based facilities.

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Section: Discussionsupporting

confidence: 83%

Section: Hh 212 Nk1 and Sk1mentioning

confidence: 53%

Section: Hh 212 Nk1 and Sk1mentioning

confidence: 99%

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Searching for jet rotation in Class 0/I sources observed with GEMINI/GNIRS

Coffey

Bacciotti

Chrysostomou

et al. 2010

A&A

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“…4) performed with the SubMillimeter Array (SMA; Lee et al 2006Lee et al , 2007aLee et al , 2008, the IRAM Plateau de Bure (PdB) interferometer Cabrit et al 2007Cabrit et al , 2012, and the Atacama Large Millimeter Array (ALMA; see Lee et al 2014;Codella et al 2014a) reveal the inner ±1 −2 = 450−900 AU collimated jet (width 100 AU) close to the protostar. HH 212 is also associated with a flattened rotating envelope in the equator perpendicular to the jet axis observed firstly with the NRAO Very Large Array (VLA) in NH 3 emission by Wiseman et al (2001) on 6000 AU scales. More recent SMA and ALMA observations in the CO isotopologues and HCO + on ∼2000, 800 AU scales indicates that the flattened envelope is rotating and infalling onto the central source, and can therefore be identified as a pseudodisk according to magnetised core collapse models (Lee et al 2006(Lee et al , 2014.…”

Section: Introductionmentioning

confidence: 75%

The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO₂emission

Podio

Codella

Gueth

et al. 2015

A&A

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Context. The investigation of the disk formation and jet launching mechanism in protostars is crucial to understanding the earliest stages of star and planet formation. Aims. We aim to constrain the physical and dynamical properties of the molecular jet and disk of the HH 212 protostellar system at unprecedented angular scales, exploiting the capabilities of the Atacama Large Millimeter Array (ALMA). Methods. The ALMA observations of HH 212 in emission lines from sulfur-bearing molecules, SO 9 8 −8 7 , SO 10 11 −10 10 , SO 2 8 2,6 −7 1,7 , are compared with simultaneous CO 3−2, SiO 8−7 data. The molecules column density and abundance are estimated using simple radiative transfer models. Results. SO 9 8 −8 7 and SO 2 8 2,6 −7 1,7 show broad velocity profiles. At systemic velocity, they probe the circumstellar gas and the cavity walls. Going from low to high blue-and red-shifted velocities the emission traces the wide-angle outflow and the fast (∼100−200 km s −1 ), collimated (∼90 AU) molecular jet revealing the inner knots with timescales ≤50 yr. The jet transports a massloss rate ≥0.2−2×10 −6 M yr −1 , implying high ejection efficiency (≥0.03−0.3). The SO and SO 2 abundances in the jet are ∼10 −7 −10 −6 . SO 10 11 −10 10 emission is compact and shows small-scale velocity gradients, indicating that it originates partly from the rotating disk previously seen in HCO + and C 17 O, and partly from the base of the jet. The disk mass is ≥0.002−0.013 M and the SO abundance in the disk is ∼10 −8 −10 −7 . Conclusions. SO and SO 2 are effective tracers of the molecular jet in the inner few hundreds AU from the protostar. Their abundances indicate that 1−40% of sulfur is in SO and SO 2 due to shocks in the jet/outflow and/or to ambipolar diffusion at the wind base. The SO abundance in the disk is 3−4 orders of magnitude larger than in evolved protoplanetary disks. This may be due to an SO enhancement in the accretion shock at the envelope-disk interface or in spiral shocks if the disk is partly gravitationally unstable.

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“…Observationally, many protostellar disks are found to be in Keplerian rotation (e.g., Wiseman et al 2001 and references therein). There are still some observed protostellar disks found to be in non-Keplerian rotation (e.g., Myers et al2000).…”

Section: Physical Properties Of a Disklike Corementioning

confidence: 99%

The Formation of Self‐Gravitating Cores in Turbulent Magnetized Clouds

Norman

Low

et al. 2004

ApJ

142

147

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We use ZEUS-MP to perform high-resolution, three-dimensional, super-Alfvénic turbulent simulations in order to investigate the role of magnetic fields in self-gravitating core formation within turbulent molecular clouds. Statistical properties of our super-Alfvénic model without gravity agree with previous similar studies. Including self-gravity, our models give the following results. They are consistent with the turbulent fragmentation prediction of the core mass distribution of Padoan & Nordlund. They also confirm that local gravitational collapse is not prevented by magnetohydrodynamic waves driven by turbulent flows, even when the turbulent Jeans mass exceeds the mass in the simulation volume. Comparison of results between 256 3 and 512 3 zone simulations reveals convergence in the collapse rate. Analysis of self-gravitating cores formed in the simulation shows the following: (1) All cores formed are magnetically supercritical by at least an order of magnitude. (2) A power-law relation between central magnetic field strength and density B c / 1=2 c is observed despite the cores being strongly supercritical. (3) Specific angular momentum j / R 3=2 for cores with radius R. (4) Most cores are prolate and triaxial in shape, in agreement with the results of Gammie and coworkers. We find a weak correlation between the minor axis of the core and the local magnetic field in our simulation at late times, different from the uncorrelated results reported by Gammie and coworkers. The core shape analysis and the power-law relationship between core mass and radius M / R 2:75 suggest the formation of some highly flattened cores. We identified 12 cloud cores with disklike appearance at a later stage of our high-resolution simulation. Instead of being tidally truncated or disrupted, the core disks survive and flourish while undergoing strong interactions. We discuss the physical properties of these disklike cores under the constraints of resolution limits.

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The Flattened, Rotating Molecular Gas Core of Protostellar Jet HH 212

Cited by 56 publications

References 22 publications

Searching for jet rotation in Class 0/I sources observed with GEMINI/GNIRS

Searching for jet rotation in Class 0/I sources observed with GEMINI/GNIRS

The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO₂emission

The Formation of Self‐Gravitating Cores in Turbulent Magnetized Clouds

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The Flattened, Rotating Molecular Gas Core of Protostellar Jet HH 212

Cited by 56 publications

References 22 publications

Searching for jet rotation in Class 0/I sources observed with GEMINI/GNIRS

Searching for jet rotation in Class 0/I sources observed with GEMINI/GNIRS

The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO2emission

The Formation of Self‐Gravitating Cores in Turbulent Magnetized Clouds

Contact Info

Product

Resources

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The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO₂emission